Polymers being characterized by high thermal stability, inert character, low coefficient of thermal expansion, low water absorption, low dielectric constant, and various degrees of Tg, among other properties, are very desirable.
These polymers may find applications requiring specific groups of the aforementioned characteristics. Recently, this need has started increasing dramatically in electronic devices. With continuously escalating sophistication in such devices, the demands on the properties and the property control are becoming rather vexatious. Especially for the electronics industry, improvements of polymers are needed in forming tough, inert, thermally stable, pin-hole free coatings, having low dielectric constant, low coefficient of thermal expansion, low moisture absorption, and high Tg, among others. Although it is not usually possible to maximize all properties, since many of them may be antagonistic, optimization as a total is highly desirable and it may be achieved if adequate control on the properties becomes available through molecular architecture or other means.
It has now been found that polyethers based on 9,9-bis-perfluoroalkyl-3,6-dihydroxy-xanthene or 9-aryl-9-perfluoroalkyl-3,6-dihydroxy-xanthene and another constituent selected from the group consisting of aryl sulfone, aryl ketone, benzonitrile, imide, and mixtures thereof, represent a class of valuable polymers promoting such properties, which are very desirable in the electronics industry.
The following references, among others, disclose polyether sulfones, polyether ketones, polyetherimides, and the like, but they do not mention, suggest, or imply the critical combinations utilized according to the present invention.
U.S. Pat. No. 4,546,141 (Gebauer) discloses a primer coating composition which is claimed to be particularly suitable for topcoating with fluorocarbon polymers. This primer composition contains
(a) 100 parts by weight of a copolymer of tetrafluoroethylene, perfluoro(alkylvinyl) ethers and if appropriate hexafluoropropylene or vinylidene fluoride,
(b) 10 to 250 parts by weight of a mixture of lithium hydroxide and finely divided silicon dioxide produced by thermal treatment,
(c) 10 to 1000 parts by weight of at least one thermoplastic resin from the group comprising the polyarylene sulfide resins, the aromatic polyether-sulfone resins and the aromatic polyether-ketone resins and
(d) water as a liquid carrier.
U.S. Pat. No. 4,578,427 (Saito et al.) discloses a coating resin composition comprising from 50 to 99% by weight of a thermoplastic aromatic polyether ketone resin and from 50 to 1% by weight of a perfluoroalkoxy resin or a tetrafluoroethylene/ hexafluoropropylene copolymer resin having hexafluoropropylene content of from 18 to 25% by weight. The composition, when applied to a steel plate, for example, produces a coating film which is claimed to be greatly improved in water repellency, while retaining the desirable properties of the polyether ketone, such as high heat resistance, good mechanical and electrical properties, and high chemical resistance.
U.S. Pat. No. 4,912,166 (Stewart) discloses a blend of tetrafluoroethylene and a poly(oxy-p-phenyleneisophthaloyl-phenylene/oxy-p-phenyleneterephthaloyl-p- phenylene) (PEKK), which is claimed to result in improved processing of the fluoroelastomer at temperatures below the melting temperature of the PEKK and improved physical properties of cured fluoroelastomer.
U.S. Pat. No. 4,942,216 (Heinz et al.) discloses polyaryl ether ketones claimed to have improved processibility.
U.S. Pat. No. 3,968,083 (Quinn) discloses polyetherimides derived from the reaction of an organic diamine and a class of dianhydrides selected from the class consisting of a bisphenol fluorenone dianhydride and a phenolphthalein dianhydride.
U.S. Pat. No. 4,433,104 (Giles, Jr.) discloses blends of
(a) a polyetherimide and
(b) a thermoplastic fluorinated polyolefin, or copolymer thereof.
These blends are claimed to have good flexural strength and flexural modulus, and to have higher impact strength than those associated with the polyetherimide components of the blends.
U.S. Pat. No. 4,612,361 (Peters) discloses fluoro-containing polyetherimides prepared from bis etherdianhydrides, fluoro-containing dianhydrides, and organic diamines. The copolymers are claimed to exhibit both increased Tg and increased solubility in halogenated solvents, which enhances their value in a wide variety of uses including films, molding compounds, and coatings.